Health class topic (3)
(Other definitions for hygiene that I've seen before include "Sanitary science" , "Principles and practice of cleanliness" , "Practice of cleanliness to maintain health" , "Clean, healthy habits" , "The practice or conditions of cleanliness" .)
(Other definitions for sex that I've seen before include "VI (Lat.); m. or f." , "Expert in the treatment of coital problems" , "Hanky-panky" , "Gender" , "This symbol is epitome of glamour" .)